Consolidate HexTool methods and add more tests

src/main/java/client/Client.java

@@ -1335,7 +1335,7 @@ public class Client extends ChannelInboundHandlerAdapter {
         try {
             MessageDigest digester = MessageDigest.getInstance(type);
             digester.update(password.getBytes(StandardCharsets.UTF_8), 0, password.length());
-            return HexTool.toString(digester.digest()).replace(" ", "").toLowerCase().equals(hash);
+            return HexTool.toHexString(digester.digest()).replace(" ", "").toLowerCase().equals(hash);
         } catch (NoSuchAlgorithmException e) {
             throw new RuntimeException("Encoding the string failed", e);
         }

src/main/java/net/encryption/MapleAESOFB.java

@@ -180,7 +180,7 @@ public class MapleAESOFB {
 
     @Override
     public String toString() {
-        return "IV: " + HexTool.toString(this.iv);
+        return "IV: " + HexTool.toHexString(this.iv);
     }
 
     private static byte[] funnyShit(byte inputByte, byte[] in) {

src/main/java/net/packet/logging/InPacketLogger.java

@@ -35,9 +35,9 @@ public class InPacketLogger extends ChannelInboundHandlerAdapter implements Pack
             final String opcodeName = getRecvOpcodeName(opcode);
             final String prefix = opcodeName == null ? "<UnknownPacket> " : "";
             log.debug("{}ClientSend:{} [{}] ({}) <HEX> {} <TEXT> {}", prefix, opcodeName, opcodeHex, packetLength,
-                    HexTool.toString(content), HexTool.toStringFromAscii(content));
+                    HexTool.toHexString(content), HexTool.toStringFromAscii(content));
         } else {
-            log.debug(HexTool.toString(new byte[]{content[0], content[1]}) + "...");
+            log.debug(HexTool.toHexString(new byte[]{content[0], content[1]}) + "...");
         }
     }
 

src/main/java/net/packet/logging/MonitoredChrLogger.java

@@ -75,7 +75,7 @@ public class MonitoredChrLogger {
             return;
         }
 
-        String packet = packetContent.length > 0 ? HexTool.toString(packetContent) : "<empty>";
+        String packet = packetContent.length > 0 ? HexTool.toHexString(packetContent) : "<empty>";
         log.info("{}-{} {}-{}", c.getAccountName(), chr.getName(), packetId, packet);
     }
 

src/main/java/net/packet/logging/OutPacketLogger.java

@@ -36,9 +36,9 @@ public class OutPacketLogger extends ChannelOutboundHandlerAdapter implements Pa
             String opcodeName = getSendOpcodeName(opcode);
             String prefix = opcodeName == null ? "<UnknownPacket> " : "";
             log.debug("{}ServerSend:{} [{}] ({}) <HEX> {} <TEXT> {}", prefix, opcodeName, opcodeHex, packetLength,
-                    HexTool.toString(content), HexTool.toStringFromAscii(content));
+                    HexTool.toHexString(content), HexTool.toStringFromAscii(content));
         } else {
-            log.debug(HexTool.toString(new byte[]{content[0], content[1]}) + " ...");
+            log.debug(HexTool.toHexString(new byte[]{content[0], content[1]}) + " ...");
         }
     }
 

src/main/java/net/server/handlers/login/LoginPasswordHandler.java

@@ -50,7 +50,7 @@ public final class LoginPasswordHandler implements PacketHandler {
     private static String hashpwSHA512(String pwd) throws NoSuchAlgorithmException, UnsupportedEncodingException {
         MessageDigest digester = MessageDigest.getInstance("SHA-512");
         digester.update(pwd.getBytes(StandardCharsets.UTF_8), 0, pwd.length());
-        return HexTool.toString(digester.digest()).replace(" ", "").toLowerCase();
+        return HexTool.toHexString(digester.digest()).replace(" ", "").toLowerCase();
     }
 
     @Override
@@ -67,7 +67,7 @@ public final class LoginPasswordHandler implements PacketHandler {
 
         p.skip(6);   // localhost masked the initial part with zeroes...
         byte[] hwidNibbles = p.readBytes(4);
-        Hwid hwid = new Hwid(HexTool.bytesToHex(hwidNibbles));
+        Hwid hwid = new Hwid(HexTool.toCompactHexString(hwidNibbles));
         int loginok = c.login(login, pwd, hwid);
 
 

src/main/java/tools/HexTool.java

@@ -22,30 +22,44 @@
 package tools;
 
 import constants.string.CharsetConstants;
-import io.netty.buffer.ByteBufUtil;
 
 import java.util.HexFormat;
 
-// TODO: use HexFormat from Java 17
+/**
+ * Handles converting back and forth from byte arrays to hex strings.
+ */
 public class HexTool {
 
     /**
-     * Convert a byte array to its hex string representation.
-     * Each byte value is equivalent to two hex characters delimited by a space.
+     * Convert a byte array to its hex string representation (upper case).
+     * Each byte value is converted to two hex characters delimited by a space.
      *
      * @param bytes Byte array to convert to a hex string.
      *              Example: {1, 16, 127, -1} is converted to "01 F0 7F FF"
      * @return The hex string
      */
-    public static String toString(byte[] bytes) {
+    public static String toHexString(byte[] bytes) {
         return HexFormat.ofDelimiter(" ").withUpperCase().formatHex(bytes);
     }
 
     /**
-     * Convert a hex string to its byte array representation. Two consecutive hex characters are equivalent to one byte.
+     * Convert a byte array to its hex string representation (upper case).
+     * Like {@link #toHexString(byte[]) HexTool.toString}, but with no space delimiter.
      *
-     * @param hexString Hex string to convert to bytes. Hex character pairs may be delimited by a space or not (compact)
+     * @return The compact hex string
+     */
+    public static String toCompactHexString(byte[] bytes) {
+        return HexFormat.of().withUpperCase().formatHex(bytes);
+    }
+
+    /**
+     * Convert a hex string to its byte array representation. Two consecutive hex characters are converted to one byte.
+     *
+     * @param hexString Hex string to convert to bytes. May be lower or upper case, and hex character pairs may be
+     *                  delimited by a space or not.
      *                  Example: "01 10 7F FF" is converted to {1, 16, 127, -1}.
+     *                  The following hex strings are considered identical and are converted to the same byte array:
+     *                  "01 10 7F FF", "01107FFF", "01 10 7f ff", "01107fff"
      * @return The byte array
      */
     public static byte[] toBytes(String hexString) {
@@ -57,27 +71,19 @@ public class HexTool {
     }
 
     public static String toStringFromAscii(final byte[] bytes) {
-        byte[] ret = new byte[bytes.length];
-        for (int x = 0; x < bytes.length; x++) {
-            if (bytes[x] < 32 && bytes[x] >= 0) {
-                ret[x] = '.';
+        byte[] filteredBytes = new byte[bytes.length];
+        for (int i = 0; i < bytes.length; i++) {
+            if (isSpecialCharacter(bytes[i])) {
+                filteredBytes[i] = '.';
             } else {
-                int chr = ((short) bytes[x]) & 0xFF;
-                ret[x] = (byte) chr;
+                filteredBytes[i] = (byte) (bytes[i] & 0xFF);
             }
         }
 
-        return new String(ret, CharsetConstants.CHARSET);
+        return new String(filteredBytes, CharsetConstants.CHARSET);
     }
 
-    /**
-     * Get upper case hex dump
-     */
-    public static String bytesToHex(byte[] bytes) {
-        return ByteBufUtil.hexDump(bytes).toUpperCase();
-    }
-
-    public static byte[] hexToBytes(String hex) {
-        return ByteBufUtil.decodeHexDump(hex);
+    private static boolean isSpecialCharacter(byte asciiCode) {
+        return asciiCode >= 0 && asciiCode <= 31;
     }
 }